<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

    <style>
        #bx{color: red;}
        .c1{color: blue;}
        h3,.c1,#bx{background-color: aqua}
        input[type="text"]{color: brown}
        input[type="password"]{color: chartreuse}

        *{border: 1px solid red}

    </style>
    
</head>
<body>
<input type="text" placeholder="用户名">
<input type="password" placeholder="密码"><br>


<h3>这是h3</h3>
<p id="bx">冰箱</p>
<p>电视</p>
<p class="c1">洗衣机</p>

<div class="c1">香蕉</div>
<div>苹果</div>

</body>
</html>